Electric brake



(No Model.)

- W. B. POTTER.

ELECTRIC BRAKE.

Patented May 26; 1896.

fl I31 \XZfNEEEE.

ANDREW B GRANAM FHOTO UTNQWASHINGYIJNDC NITED STATES ATENT FFVICE.

\VILLIAM B. POTTER, OF SCIIENECTADY, NEIV YORK, ASSIGNOR TO THE GENERALELECTRIC COMPANY, OF NEIV YORK.

ELECTRIC BRAKE.

SPECIFICATION forming part of Letters Patent No. 560,751, dated May 26,1896.

Application filed March 1 S 1 8 9 6.

To all whom, it may concern:

I Be it known that I, ILLIAM B. POTTER, a citizen of the United States,residing at Schenectady, in the county of Schenectady, State of NewYork, have invented certain new and useful Improvements in ElectricBrakes, (Case No. 179,) of which the following is a specification.

My invention relates to electric brakes, and has for its object toprovide a braking apparatus which shall be operative in whicheverdirection the car may be moving and which shall also have an interlockso arranged as to prevent its improper manipulation. To the ends pointedout I arrange my controller for the improved braking apparatus withthree cylindersone for the ordinary control of the motors in propellingthe car, the other the usual reversing-switch, and the third a switchfor converting the motors into generators and utilizing the current inbrakingmagnets or otherwise to arrest the motion of the car. This latterswitch is of peculiar construction, and the interlock adapted to it isalso a peculiar one. The switch has two directions of rotation from itsoff position, these two directions corresponding to the two positions ofthe reversing-switch. hen the reversing-switch is in the forwardposition, or that corresponding to the position in which the motorspropel the car forward, one set of contacts upon the braking-switch areutilized to arrest the motion of the car, and the position of theinterlock is such that the braking-switch handle can be rotated only inthe direction rendering this set of contacts operative. \Vhen thereversing-switch, however, is in the backward position, then the otherset of contacts upon the braking-switch is to be brought into play, andthe interlock is arranged so that the handle of the braking-switch maybe operated to bring this set of contacts into operation.

The accompanying drawings show an embodiment of my invention, Figure 1being a plan view of the controller with the cover removed, showing thearrangement of the interlocking mechanism; Fig. 2, a front elevation,partly in section, also illustrating the interlock. Figs. 3 and 4 aredetails more fully described hereinafter; and Fig. 5 is a diagram ofSerial No. 583,019. (No model.)

the circuits, which are cylindrical, developed in plane. Y

In Figs. 1 and 2, A is the back of the controller, and B is the cover.In suitable bearings are mounted the three switching-cylinders D E F,operated, respectively, by the handles C C C these parts being of theusual type. These cylinders are provided with step-by-step devicesconsisting of ratchets or, as they are now called in the art,star-wheels D E F, having notches in which fit pawls L G H I I, providedwith the usual cam-rollers and held in place against the star-wheels bysprings N N. Upon the cylinder D is a collar P, provided with a slot P,with which the pawls G H may register. Another collar 0 is provided uponthe reversing-switch shaft, having two notches 0 O in which the pawls II may respectively be inserted. The detail of this collar is best seenin Fig. 3. The star-wheel F upon the braking-cylinder is illustrated inFig. i. It consists of two parts in different planes, the upper oneadapted to operate the pawl I and the lower one operating the pawl I,the latter construction being best seen in Fig. The two pawls I I havetheir bearin g in a suitable lug depending from the top of theapparatus. The pawl II is carried upon two links K K journaled in lugs KK upon the back of the apparatus. The link K has a fork upon its endwhich embraces both of the pawls I I, so that whichever one of thesepawls is operated the pawl II will also be ac tuated thereby, andwhichever one of the pawls I I is not operated by the proper portion ofthe star-wheel F will remain at rest, the fork being free to move overit.

The operation of the device thus described is as follows: Thecontrolling-cylinder D is illustrated in its off position, thereversingswitch cylinder E in its forward position. In this position thenotch or slot P in the collar P is in alinement with the two pawls G H.The braking-switch cylinder F being also at its off position, any one ofthe three handles may now be operated. If the reversingswitch handle Cbe operated, it will be brought first to its middle position, and inthis case the portion of the collar 0 intermediate between the notchesO' 0 would be brought opposite the two pawls I I and the motion of thebraking-switch would be prevented, inasmuch as these pawls would lookits star-wheels in place. In this position all of the cylinders would belocked against motion, inasmuch as the pawl G would also be inserted inthe slot P, locking the controlling cylinder. The further rotation ofthe reversing-switch handle would release the other two cylinders assoon as the cam-roller upon the pawl G fell into either the forward orback notch of the star-wheel E; but assuming the reversingswitch handleto remain in its illustrated position, the controlling-cylinder D may berotated as desired. Allowing it to remain in its illustrated position,if it be attempted to rotate the brake-cylinder F it may only be rotatedclockwise, the handle 0 moving toward the operator, inasmuch as (seealso Figs. 3 and 4) the lower part of the camwheel F operates the pawlI, which is free to move in and out of the notch O of the collar 0, theupper part of the wheel not operating the pawl I. This brings intooperation the proper set of contacts upon the braking-cylinder, havingreference to the connections between that and the reversing cylinder,which will presently be described. With the reversing-switch handlethrown to the backward position, the operation of the brakingswitchwould, however, be reversed. As in this case the notch 0 would no longerbe in alinement with the pawl I, the motion of the braking-switch handleO must be reversed, as that pawl would then strike against the collar 0and prevent its operation in the former direction, the pawl I, however,being free to move in and out of the notch 0.

Referring now to Fig. 5, I illustrate the circuits of the apparatus. Thenecessity for the characteristic interlocking arrangement will beapparent from this figure. The cylinders are lettered as in Figs. 1 and2, the contacts being developed in plane and being numbered upon thecontrolling-switch 1 to 8, upon the reversing-switch 9 to 14, and uponthe braking-switch 15 to 24 and 15 to 24. The motor armature is letteredMA, the motor-field MF, the trolley T, and the brakeshoe BS. The smallcircles represent the fixed contacts for the various cylinders. The0011- trolling-switch D is one adapted for the ordinaryresistance-control with a single motor. I may, however, employ aseries-parallel or any other form of controller, inasmuch as this formsno part of my invention. It will be understood readily that thedifferent contacts of the controller short-circuit different parts ofthe resistance R until it is entirely out out. In its first position thecircuit would be as follows: from the trolley T to contact 1, to contact2 of the controller, thence to contact 9 upon the reversing-switch, tocontact 9, to contact 26 upon the braking-switch, to contact 26, throughthe motor-armature, to contact 25, to contact 25, to contact 10 upon thereversing-switch, to contact 10, through the motor-field MF, through theresistance to contact 7 upon the controller, to contact 8, and out atground.

\Vith the controller at the off position and the brakingswitch andreversing-switch in their illustrated position the circuit is open,butupon operating the brake-switch to bring the fixed contacts upon theset of contacts 15, &c., the circuit is closed through the brake-shoe BSand resistance R, as follows: Starting from the plus brush of themotorarmature the current passes to contact 26, thence to contact-plate22, to contact-plate 23 through the brake-shoe to 24, to contactplate21, contact 25, to contacts 10 10 upon the reversing-switch, through themotor-field and resistance, contact 19 upon thebrakingswitch, to 20",contact 25, and back to the minus brush of the motor. The furthermanipulation of the brake-switch serves to cut out sections of theresistance, permitting the generation of more and more current and agreater and greater magnetization of the brake-shoe until the car isfinally brought to a stop. When, however, the reversing-switch is uponthe contacts 11 to 14, or in its backward position, the contacts 15 to24 of the brakingswitch are utilized. The circuit would then be asfollows, the relation of armature and field being reversed relatively totheir former connection, the current leaving the minus brush of themotor thus passing through the field in the proper direction, forwell-known reasons: from the minus brush of the motorarmature MA tocontact 25, to contact-plate 20, to contact-plate 23, through thebrake-shoe to contact-plate 24, to contact-plate 22, to contact 26, tocontact 9 upon the reversingswitch, to contact 12, to contact 14, tocontact 10, through the motor-field and resistance, to contact-plate 19upon the braking-switch, to contact-plate 21, to contact 26, and to theplus brush of the motor-armature.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. In an electric braking apparatus, the combination of acontrolling-switch, a reversing-switch, and a brakingswitch having twosets of contacts corresponding respectively to the forward and backwardrunning positions of the reversing-switch, and means for locking theswitches so that only one of the switches may be operated at one time,the interlocking means being so arranged that the braking-switch may beoperated only in a direction corresponding to the proper position of thereversing-switch.

2. In an electric brake, the combination of a controllingswitch, areversing-switch, and a braking-switch provided with two sets ofcontacts corresponding to the forward and backward running positions ofthe reversing switch, and an interlock between the reversing-switch,controller and braking-switch; the interlock arranged to permit theoperation of the braking-switch in one direction when thereversing-switch is set forward, and

in the other direction when the reversingswitch is set back.

3. In an electric brake, the combination of a controlling-switch, areversing-switch, and a braking-switch having two sets of contactscorresponding respectively to the forward and backward positions of thereversing-switch, a pawl operated by a cam upon the reversingswitch tolock the controlling-switch, a second pawl operated by thebraking-switch and looking the controller, and a pair of pawls operatedby corresponding starwheels or cams upon the braking-switch, one of saidpawls locking the reversing-switch in its forward position, the other inits backward position, and one being operated by the rotation of thebraking-switch in one direction, the other by its rotation in theopposite direction. 111 witness whereof I have hereunto set my hand this9th day of March, 1896.

WILLIAM B. POTTER. lVit-nesses:

B. B. HULL, A. F. MACDONALD.

